1. Field of the Invention
This invention relates to apparatus in a tractor trailer combination for connecting and disconnecting a trailer and bogie to obtain a desired wheel loading of the bogie axles and to prevent accidental separation.
2. Description of the Prior Art
It is well understood that the use of the interstate highways by improper axle loading of the tractor-trailers is a significant reason for deterioration of pavement surfaces and why the highways are being repaired almost constantly. One way to alleviate the problem of improper axle loading which contributes to highway damage is to shift the trailer bogie along the body of the trailer to change the axle loading to one that is mandated to be within an axle loading value. Besides creating undue pavement wear, improper axle loading can also cause loss of driver control and jackknifing.
In order to shift a bogie, apparatus has been devised to manually disconnect the bogie from the trailer slider and operate the braking of the bogie so the trailer can be moved in the proper direction to transfer more or less load on the bogie axles. The manual operation is not only time consuming but it requires in most cases the assistance of a helper. Apparatus has been devised for allowing the driver of the tractor to effect a shift in the position of the trailer body relative to the bogie, but problems still remain to effect the locking and unlocking of the bogie in such a way that a secure locking of the bogie in a desired position can be obtained every time a shift is necessary. Other problems are found in the arrangement of the operating mechanism which effects an interlock between a trailer and its bogie. The manual operation for shifting a bogie is often very strenous especially when a trailer is loaded as the friction between the trailer slider and the bogie pin is increased. The pins often stick and must be struck with heavy mallets or sledge hammers by a helper while the driver attempts to rock the trailer as the helper applies manual force on the pin lever mechanism while hammering at the pins. Many injuries have occured to helpers as a result of the physical strain and from falling in the path of the bogie wheels.
If no helper is available, the driver many times can only proceed one slider hole at a time if constant pin retracting force cannot be maintained on the lever which counteracts the spring action which drives the pins into locking positions in the next slider hole that is reached. If the driver overshoots or undershoots the hole the procedure becomes even more time consuming.
There is also a currently existing problem in that a driver can release the brakes and drive the tractor away without the locking pins being inserted into the slider holes. In such cases, the pins are merely being pushed by the retaining springs into the sides of the slider rails so that no secure interlock of trailer and bogie is obtained.
Presently, there is no device being used which would prevent the brakes from releasing until the pins are properly secured. So presently, the trailer can be moved without the pin locking the trailer and bogie together which invites highway accidents when the two separate on the roadway